Nut and screw feed



M2467@ Apr111z,1927. SMRANSOME NUT AND SCREW FEED Filed May 2l, 3.925` 2Sheets-Shea?. 1

L1/aa 5 l5 l50 f d6 April 12, 1927.

S. M.l RANSOME NUT AND SCREW' FEED Filed May 21, l1,326

2 Sheets-Sheet vl2 'Patented Apr 12,1927.v

A g 1,624,575 en,

roRnfiL-Lin'ois, 'nssienon a 'ro Birmaniecomvrmvv A"loonrionnrionoEaLLINoIs.' f

' Y n appnati'qn fnedlnay 271, 1525.- sena;nelenses..Y f

feeds, and rvin.particular to means terrenipensati ng' for linaccuracies the thread ot' afeedscreivl' I l 'Y i Heretoforeinmachin'etoolshaving parts Afed by va screiv 'acting' on anut', theaccuracy- =ofltheworky done by thev machine has'beenv dependent'upon'the accuracy or" the screwv feed. jFor some Work inaecuraciesofthescretv'may be compounded by producing inl, accurate tools which are usedto produc-e other tools or parts."Tl1erefore, it is 'quite' tions into al essential, in order tos'ecurethe' greatest greeo't accuracy, to useaccurate reed screws orto use meansto compensate 'for possibleinaccuraciesofthe yfeed screw. FA; common detect ot feed screwsy is layvariation "inthe Y rate of advance ofthe helical thread, which leadst-o`ftl1e,so-called` drunkenness et the iced.` V`rl f H 1 f f Thepri-mary object of thisfijnvention 1ste provide a' simpleVcompensatingfdevice for correcting the drunkenness of iced screws."v

i ylrnthr lobject 'of the inventionfis to pro-i`l vide a plurality zoli:parts' acteduponby thevv i vantages' of the present invention willbe vshown in 'thef accompanying" drawings parent from the followingdescription ot an exemplary j embodiment of ,tlieinvention 1n i the"correcting ymechanisni partly inl elevationjg 1 Fi is,v 'across-sectional,view`taken substantially'on theLline-Q-fot Fig. 5.y I' u1 Figff is a cross-ssectionalvieja7 italien" on' ol the 'averaging'ineehanisniff j p F ig. 4 iisgacrossfsectional- 'vicivon the" lin" lf-lof Ishowing the oth: fend'otjt e' av'eragingineclninism.v 55 fFigQtlfsacross-sectional v'eiv 'onthe line velopment the nut segments. iv Y v 'y Fig. 6 isa rectified projeetioniii elevation of the correctingnut and of' the feed screw, the/threadof the screw/being 'indicated asa" perfect' helix.

showing the arrangement of ig. `Tis avieyv similartoFig. Gishowing Intlie'foiloiving vdescription of the device illustrated 'in Athe`drawings, Ythe particular the 'construction shovnlV It :Will beapparent,

lin view ot the ft'ollowing eXplanation tof the invention, 'thatalternative constructions and arrangements ofthe parts are hereincontemplated by the mventioi'i'as expressedvin the f'Referring"particularly "toy the drawings, I show -a i-eedsc're 10, suchas 1s commonly used toxmovecarriages VViii-"lathes, bobbing aininaccurate helical:,thread onfthe'` feed l Vembodiliient.of theinventionis .not'to be construed as a"lnn1tation of the/inventionv to machines',and other" 'machine-tools. The

feedscrewi'ha's thereon a helical-thread 11.V

When the thread is perfect-helix, afplane Vdevelopment'thereof may lbe1represented by a series of straight lines, as in Fig.A 6;" When,-A

-however, ycertain portions otfthethr-ead advance morefrapidly thanothers,v a plane de` thereof AWould be-represented by as'eries otfivavylines, as in YFio'df? .1, V

Means is provided bet-Ween the screwV and the/*machine part'zledtherebyjto: advance sucli'machiiie partjrelatively along the icedYVscrew"by' the vrotation of one -ol the memf bers,y said means servingto compensate for. lrregularitiesin ythe helix of the feed screw.

` In .thepresent instance, this `is 'eifectedby means; in the-form yof,a Dlurality" of mentrbersY "bydifferent-portionsof the feed seieias',for eiiai'nple,V anutcomposed ofA sectionsf!which4v are so related .thattliejin-f nient' isthus'inade to be theaveraag'emotion1V the sectionsused bejarcuatfe"'segments cirv imrerentially fplaced'f about thescrewfso tha'tthey'form 1in eifectalsin'glenut.

l In' vthe"'presentiinstance, suchfai'nutfisf composed;otiour arcuatesegment-s l2, 13,

l l. fand' "71.15. eachbeing substantially qua-rfv ter. l section ot anut, VMeans is employed te hold' the segments circumferentially rigiddep'endentac onfot thefscretv'oneachsec! tion-A istransnnttedy to "anintermediate felesV ment] The" motion of the vintermeciige ele-"',ot'tlre various sections. ""Itfi's pieferablethat i quired thisbeingV a cylindrical casing 16, in which the segments are held to permitlongitudinal motion by suitable guiding means. Such means is shown inthe form of a key 17,

disposed between the segments and the container, the keybeing-fixed inone part and movable in a key-way in another part, such as the key ways18 herein shown inthe container 16.

In the rotation of an arcuate feed screw, the segments forming the nutare equally advanced simultaneously. lVhen inaccuracies such as those ofthe thread 11b are present in thehelical thread, some segments will beadvanced slightly more than the re amount,.some may be' correctlyadvanced, andothers will be slightlyy retarded, the average of theadvance of all the segments corresponding substantially to the advancewhich would resultfrom a true helix 11. Accordingly, the inventionincludes means to average the advances of the segments and to transmittheVV average advance toa carriage or other element to be moved by thescrew. In the present instance, theV element to be advanced is thecontainer 16. A vring cap 19 is placed overt-he end of the container 16,the cap being suitably secured thereto asby the screw 20. The ring 19passes freely over the screw 10 and serves to take the thrust of the nutsegments, the averaging mechanism being interposed between this ring andthe segments.

The averaging mechanism comprises, in the present instance, a segmentalring corresponding preferably in number of segments te the segments ofthe nut, in the present instance four, the ring segments being here indesignated as 21, 22, 28 and 24. Unlike theV nut, the ring has itssegments fixed yagainst longitudinal motion axially ofthe ringrelatively to each other, and further has its segments free for relativecircumferential motion in the planelof the ring about its axis. Invorder to limit the longitudinal motion ofthe ring segments, va fixedring 25, is employed in abutting relation to the ring cap 19.' Aplurality ofl bearing balls 2G lare placed between the thrust bearingring 25 vand the segmental ring. One sidev of the ring segments ispreferably grooved as at 2T to receive the balls 26. Retaining meanssuch as the'pins 28 are associated with each segment to retain apredetermined number offtl'ie balls 26 always stationed in the race27 ofeaclrsegment. v In the presentv construction .three balls are soretained.

-lo equalize or average the thrustof the nut segments against the ringsegments I employ wedging means between the ring segments, thel wedgingmeans being acted upon by the nut segments. In the present instance thewedging means is provided by forming each end of each ring segment withLdoubly beveled notches 29 on the sideadjacent the nut segments, theadjacent bevels 29 forming a V-shaped or pyramdal recess between adjacentsegments which can ber widened by a separating motion of theadjacent ring segments. The advance of the single nut segment is madeeffective at the beveled ends 29 to cause the separation of the ringseginent-s, and for this purpose there is employed a Vsingle ball'SOVacting on the two opposing notches 29l by the advance of one ofthe nutsegments.` The ball 30 is preferably placed at the center of the nutsegment. A hardened piece of steel 31 may be suitably'mounted in the endof the nut segment where the ball 30 bears thereon, the hardened piecebeing held in position by means such as a pin 32 whereby the piece isreadily removable. The bearing piece 31 is preferably set belowA thelevel of the end of the nut segment in a' suitable recess, therebyforming shoulders 33 which rserve to keep the ball 30 stationedsubstantially always at the center vof the nut segment.

In the operation of a machine embodying this invention, let itv besupposed that th helical feed screw lO has an irregular thread helix, asshown in Fig. 7. It is obvious that the ordinary nut, commonly foundinmachines of this character, would be advanced noneuniformly by auniform rotation of the feed screw. However, by providing the machinewith a nut embodying the present in vention, the inaccuracies aresmoothed out and are avera'ged'towards a uniform advance of the compoundnut, the accuracy ofthe averaging,` of course, being dependent upon thenumber of segments forming the nut. By reference to Fig. 7, representinga thread of the feed screw and a plurality of segments in rectifiedprojected elevation, it is obvious that rotation of the feed screw willcause the nut segments 12, 13, 14: and 15 to be out of line, as shown,compared to their *position in Fig-6. whereina true helix 11a is shown.InV Fig. 7, the segments13 and 15 are shown advanced Y,beyond thepositions occupied by segments 12 and 14. The advanced segments 13 and15 aie shown to have forced the balls 80Vforward against the beveledlbearing thereon to withdraw from the ring segments, thus permitting theadjacent ring segments to approacheach other as they are separated fromthe opposite ends by the advanced nut segments. It is clear that as ktherelative positions'k of the nut. segments are reversed from that showninFig. 7 the ring lll) lle

' segments likewise .move into'a different posi magere :'vtion, tliusserving tocause any averagingL effectofthe longitudinal motion of thenuts egn'ients.l The averaged motion is then iin` partedthrough the balls26l to the ring'u and thence tothe-ring cap.l9,fwhic'h inthe f presentinstance is Secured to the container lG,l,thus causing it to advancewith the segments contained therein, thejwhole forming a compactcorrecting devicev of great simf plicity.1

Ilelaiin as my invention:

A nut and screw feed devicey comprising-,fin combination, a feed screw,la plurality ofrnutsegments circuinferentially arranged* lfaboutY thescrew in non-rotationalrelation with vrespect .to eachother, each ofsaidl segments being. independently movable axiallyl Y tial motionwithi'espect to4 eachother about the vfeed screw, there being at leastasmany ring segments as nut segments, and meansv 'associated with eachnutA segnientto ,sepa- 1,

ratetwo adjacent ringv segmentsbyy Van.V ad-I vance of a nut segment.V

2.1L nut. and screw feed devicecompris-.-

' ing, inconibination, a feed screw, aplurality of nut segments,circumferentially arranged about thev screwl in non-rotationalrelation@l with respect to each other, each ofsaid seg'- inents beingindependently'movable axially of tlie screw, a plurality of ringsegments arrangedV circumferentially about thefeed ,-.tially arrangedring segments .about the screw, the nut segments being axiallymov`screw, saidY ring segments being held against motion relative to eachother axially of the feedscreivand beingfree for circumferentialmotionivitli respect to each otherfabout 'the feed screw, therebeing-atleast! as manyV g ringsegiiients 'as nut segmentseach of saidring segments having beveledl ends forming a V-notch opening towards thenut segments, and a ball in said-KV-notch in engagen'ient withthe end ofa'nut segment. Y V

3." A -nut and screivv feed device con'ipris.-

ing, in combination,.ayfeed screw, a pluralf'yityof;circumferentially.arranged nut Segnieiits and a similar Vnumber ofcireumleren- 4tween tlienut segments and then-ing segtheringVV segmentsbyfuiiequal l-ongitudinalf Y A im y 1 tially arranged ring segmentsabout the screw,

the nut segments being axially movable and circuinferentiallyin'iinovable lu-"ith respectlo ach other, the --ring segments beingcircunr, ferentially movable and axially, fixed ywith respect to Aeachother, vmeansdisposed bel tween the nut segments and the ringsegf mentsto effect circuinfereiitialv motion-of the ring segmentsby unequallongitudinal inof. tion of tlileinutsegments, and means held in abuttingielationto the ring segments in the.. plane thereof to be .moved therebyin the geii--j eral fadil'ance of the. `nut fse'gn'ients by the A@ nutand screw feeddevicelcomprisy 8O ing, incoin'biiiation, Va feed scr-civ,a ,plural i' it'yof eircuinferentiallyr arrangednut. segu,

ments, a similar number of Vcircumferentially. arranged ring segmentsaboutftlie scie\v,the nut segments being'axially movable and circuinferen'tially imn'iovable Wit-lr respect to eaclibtlie'rhthe ringjsegn'ients being circuisi-v 'p -ferentially movable jpaiid'v'axially"iixed y with 4'respect' .to/ leach other, fmeains disposed bef ments toeffect circumferential motion of the `ring segmeifitsv lay-unequalVlongitudinal'in o-` tion of thenut segments,fan annular member.,

r about said screw, vand al pluralitylof bearing. f

balls-y disp-osed between vsaid segmentsanditlf" .said annular member.lA

A nut and screwfeed device comprising,`v in ,coinbinatioma feedscrew, aplurality of circuinferentially ,arraiiged Ynut segments, a similarnumberjof circumferentially;v i ranged ring-segments about tliejsereiv,f e nut segments 'beiiigraxially movable andcir'-cumferentially,'immovable with' respect to each other, the ring segmentsbeing circumferentia'lly movable and axiallyfixedy'ith "i" respect toYeachother, means dispose'drV bes; tween the nutsfegnients andthe ring-i'i ments toreffect1circumferential iii-otionof motion-of.thenutiseginents, each ring seg-1. ment haring a balli-ace formed fuponthe outer side thereoha plurality of balls` in vsaid race,i"etaini 'iigmeans forsaid ballsgiiiil an annular? member :about the .sci-ewv forni--ing Va bearing surface for, said ,ballasaid member'serving` to receivethe-i'liiiist `oA "he vladvancing nut segments. 1

'7. 'A nutandV screw feeding'device conil able and circumferentially`immoiv'able with fl'irising :in combination, a feed sci'ewL-agjcasiYrespect `to each other, the ring segments be?A ving circumferentiallymovable and axially ing surrounding said screw,vsia'id casing-ibm' ingfreely.slida-ble.along thelfeed screw, a

fixed ivith respect vtoeach other, and"meansfv'pliirality ofvinitsegments "in said casing'held ,tion of the ring segments by unequalvlongidisposcd between the ,.iiut segments and Vthe' ringV segments toeffect circui,nferent'ialv mo-V tu'dinallinotion ofy the Vnut segments.

il. A nut and screw feed .device compris-z" ing,inicombination,ajfeedscrew, a plural-` ity of -circuinfereiitially arranged nut seg.` ments,a similar Vnumber of circum'fereii-- Aalong thedirection f the screw,'an ann `cap over one endvof the casingI rigidly;

non-rotatably'-"tlierein and freely"V sl.

imi

se'g'nientsl adjacent ring' segments be' Yfree- 'ly movablecircimiierentially with reicrencc to each other, and wedging meansassociated with each nut segment to enter between adjacent ring'segments for separating' them by an advance ot the nutscg'ments. i

YS. A nutand sci'ew feeding device coinprising', in combination, a-eedscrew, an ele- Vment to be advanced by Vrotation of the screw, aplurality otnut-acting members advanced i'elatively by various parts ofthe feed screw, and means between said nutacting' members and saidelement totransmit the average advance of the members to said element. Y

9. A nut and screw feed device comprising', in combination, a feedscrew,an element to be advanced by rotation of the screw, a

vplurality ot nut-acting' members positioned to beadvanced relatively byadjacentarcuate portions ot the screw, and 'neans between said nutacting members and said element to transmit the average advance ofthemembcrs to said element l0. A nut and sci'ew teed device, compris-Aing', in combination, a teed screw, an ele-V ILA nut and screw teeddevice, comprising, in combination, a feed-screw, an element to beadvanced relatively by rotation ofthe screw., a plurality of membersarranged to be advanced simultaneously by different portions loi thescrew, means interposed between said' element and said members totransmit the'avei'age advance of themembers .to the clement` saidmeans'i'ncludrng' a. ring' composed ot circumterentially movablesegments, which are axially fixed with respect to eachl other, and meansmoved by the members entering' between adjacent segments of the ring' toeiiecta separation thereof by the adrance ot a member.

l2. ln a device of the character described, an averaging mechanismcomprising', in coin'- binati on, an abutment member', a ring' acting'against said member composed `ot a plui'ality'f.

ot segments movable circumterentially with respect to; each Yother andVwedg'ing' means acting between said segments, and movable members.bearing against said wedging 13. In a device ot the characterdescribed,

an averaging' mechanism comprising', in cembination, an abutmentmember., a'ring' acting',`

sections. Y Y y 18. A, correcting' device torthe inaccura-` a gainstsaidmember composed of a plurality of segments movable circumferentiallywithrespect to each other, aplurality of bearing balls between said memberand said seg'- nients, retaining' means on each segmentrto retain aiixed numberof balls always'in asso-Y ciation withV each segment, andfwedg'ing.

means entering' between the adjacent segments, and movable i membersagainst said wedg'ing' means.

14. lna device ot' the character described, a correcting nut comprising,in combination, a container har/*ing a cylindrical recess therein, aplurality of longit-udinalnut segments therein, a ley way in thecontainer for each segment, a key on each segment slidablein aV key'waywhereby to hold the segments axially movable and circumterentiallyimmovable,` a cap secured over the end of the cas-' Aifig, aiid anaveraging' mechanism acting 0n the cap rand acted upon by the segmentswhereby to move the container with a motion which is the average of themotion 'ofthe segments;

l5. in a device of the character described,

a correcting' nut comprising',in combination,

a container having' a'recess therein, a plurality ot longitudinal.arcuate nut segments in said recess, guiding' means disposed betweeneach segment and the container' whereby to iold the segments axiallymovable and cir cumterentially immovable with' 'respect to each other,capping means over the end oit said container and rigidly'securedthereto,

and an averaging mechanism acting on the capping' means and acted uponby the seg'- ments whereby to move the container with a motionwvhich isvthe average otA the motion ot the segments. i y

'16. A correcting' device for inaccuracies ot feedscrewscomprising, incombination, a plurality ot Vmembers arranged to be advancedindependentlyby a feed screw, and

means'aifected by each-of said members to average the advance'or" all ofsaid members.

17. A correcting' device-tor the inaccuracies of 'feed screwscomprising', in combination, a j'alui'ality'ot nut sections varranged tor be acted upon by the Vfeed screw, an element to be advanced by all ofvsaid nutsections.

and means between said element and each of said sections to average-theadvance of' rthe cies' ci teed screws comprising',"in combination, a nut'formed ott a plnrality ot sections i longitudinally movable relative toeachother axially ot the nut,andmechanism associated therewith toaverage the separate advances or" the nut sections. Y ln testimonywhereof, I have hereunto affixed my signature.`

s'rArronn M. nANsoMn.

bearing'

